Lecture 13 - Prokaryotes: Bacteria & Archaea Flashcards
What 4 external structures do prokaryotes have that differ from eukaryotes?
- Cell wall composition
- Fimbriae and capsule
- Pili
- Flagella
What 2 internal structures do prokaryotes have that homologous/analogous functions to eukaryotic organelles?
- Aerobic prokaryotes have respiratory membranes like mitochondria
- Photosynthetic prokaryotes have thylakoid membranes like chloroplasts
How do prokaryotic chromosomes differ from eukaryotic chromosomes?
Prokaryotic chromosomes are not bound, are circular, and contain less DNA.
What are plasmids?
They are small rings of DNA that replicate independently and are found in prokaryotes and some fungi.
Which 2 of the 3 domains are more closely related?
Eukaryotes are more closely related to archaea than archaea are to bacteria.
How do bacteria and archaea differ in how they survive extreme/bad conditions?
Archaea are extremophiles and bacteria tend to change form into endospores in bad conditions.
How do prokaryotes and eukaryotes differ in how they reproduce?
Prokaryotes reproduce through binary fission and eukaryotes reproduce through sexual reproduction.
How is genetic diversity generated in prokaryotes?
It is generated through mutation and recombination.
What is transformation?
Foreign DNA from the environment is transported into the cell and proteins express it as chromosomal DNA or plastids.
What is transduction?
A phage infects bacterial donor cell and replicates its DNA within the host cell, killing it but maintaining some of its DNA. Crossing over then leads to recombination of DNA by joining chromosomal DNA or forming plastids.
What is conjugation?
It is the only way to see a direct exchange of genetic material in prokaryotes. An f+ and f- cell connect through a meeting bridge and an f plasmid moves from the donor to the recipient cell which replicates it to become an f+ cell. The donor cell replaces the broken strand so they are both f+.
How do short generation times allow prokaryotes to evolve quickly?
Mutations can quickly accumulate which creates an opportunity for selection.
How does horizontal gene transfer allow prokaryotes to evolve quickly?
It allows for the recombination between different species which leads to novel genes.
How do plasmids allow prokaryotes to evolve quickly?
Plasmids are bonus mobile DNA with high genetic variation which is useful for adapting to new environments especially because beneficial traits are usually under rapid selection. This is important for antibiotic resistance.
What are 3 major roles eukaryotes play in the environment?
- Decomposition
- Oxygen production
- Nitrogen fixation
